Island



(No Model.)

V. A. THOMAS'. CARBON CLAMP FOR ARG LIGHTS.

Patented Sept. 22, 1891.

W LTN EEEEE.

.UNITED STATES "PATENT v OFFICE.

VAN A. THOMAS, OF PROVIDENCE, RHODE ISLAND, ASSIGNOR OF ONE-HALF TO ANDREV D.v ROSS, OF SAME PLACE. i

CARBON-'CLAMP SPECIFICATION forming part of Letters Patent No. 459,845, dated September 22, 1891.

Application tiled December 27, 1890. Serial No. 375,983. (No model.)

tion of the invention, such as Will enable oth-A zo ers skilled in the art to which it appertains to make and use the same, reference being had to the accompanying drawings, and to letters 0f reference marked thereon, which form a part of this specification. j Y

My present invention has relation to detachable carbon-clamps for arc lights; and it consists in the combination of two jaw members having their lower portions arranged to receive and clasp an end of the upper carbon. 2o One of the said jaws is normally stationary and adapted to be secured to the carrier-rod of the feeding device, the other jaw being provided with tWo upwardly-extending ears and jointed to the other jaw, and a collared thumbscrew tapped into the stationary jaw, the collared portion at the same time being in engagement with the ears of the movable jaw, all as willbe more fully hereinafter set forth.

Heretofore carbon-clamps of the class re- 3o ferred to have usually been so constructed that-the movable jaw was practically loose and independent of the other jaw and screw. l

There are disadvantages or objections to the use of such former clamps. In opening the clamp by means of the screw the movable jaw frequently fails to follow the screw, thereby causing the trimmer considerable trouble and loss of time before he can replace anew carbon in the clamp or holder. Sometimes the carbon becomes burned onto the clamp, the loose jaw preventing the trimmer from readily detaching it. Sometimes the trimmer will unconsciously unscrew the clampingscrew from the stationary jaw into which it is tapped, thereby permitting the loose jaw to fall to the ground.

By means of my improvement all the foregoing disadvantages are overcome, because, first, the movable jaw is jointed to the other 5o jaw. Consequently it cannot drop out even though the screw be removed, and, second, the

screw itself is provided with collars so arranged that the jointed jaw is forced to always move laterally in unison with the screw. The cost of the carbon-clamp is practically no greater than clam ps nnprovided with my improvements. y

In the appended sheetof drawings, Figure l is a side elevation of my improved carbonclamp. Fig. 2 is a plan view. Fig. 3 is an inverted end view. Fig. 4 is a longitudinal central sectional view of the device. Fig. 5 is a side elevation of the movable jaw detached, and Fig. 6 is a side view showing the jaws fully separated.

The clamp or holder as a whole is designated by A. The stationary jaw ais provided with a top portion a', from which extends a lateral projection or ear a2, the latter being drilled to receive a joint-pin p. b indicates the other or movable jaw,having two parallel elongated sides or ears b, arranged to receive the ear a2; The jaw b is jointed to the stationary jaw by means of a pin p passing through the said parts ZJ and a2, as clearly represented.

s designates a screw tapped i'nto'the upper portion of the jaw member a. The opposite end or head is provided with a thumb-piece s to facilitate the turning of the screw.; The head portion of the screw is also provided with two collars e e, arranged to receive and engage opposite-sides of the ears b', the Stem of the screw at the same time passing freely between the ears, as represented by the drawings. The inner vertical sides of the lower portion of the jaws are preferably made angular (see Fig. 3) in order to clamp the cariirmly. The end o. of the jaw a is tapped to receive the end of a carrier-rod r. (See dotted lines, Figs. 4 and 6.) When in use, the centers or axes of the rod r and carbon c should be in line. As the carrier-rod and its other attached mechanism form no part of my present invention, therefore I deem it unnecessary to further illustrate and describe them.

Now from the foregoing it will be seen, as before' stated, that an arc lamp provided with my improved carbon-clamp possesses advantages over lamps using the ordinary form of bon c (see dotted lines) more readily and- IOO carbon-clamp. The movable jaw cannot,when

in use, become detached and fall. The screw itself cannot be entirely unscrewed unless the joint-pin 1J be first withdrawn and the jaw b positively follows the movement of the screw, thereby readily permitting the trimmer to remove the burned carbon and replace it by a new one.

In lieu of the pin p, the movable jaw may be made to interlock loosely with the other jaw, although I prefer the arrangement as shown and described. A spiral spring might be substituted for the inner collar e of the screw, the action of the spring being to force the jaw b outwardly upon unscrewing the threaded stem s. An objection to the use of a spring is that sometimes the carbons are nearly consumed before being renewed. In such case the clamp, &c., become very hot, thereby destroying the efflcien cy ofthe spring.

I claim as my inventionl. The carbonclamp hereinbefore described, consisting of a normally-stationary jaw member adapted to be secured to a carrier-rod, a movable slotted jaw member jointed to the other jaw, the two jaws being arranged to receive and hold a carbon, and a collared clamping-screw tapped into the stationary jaw and having the slotted portion of the movable jaw in engagement with the collared part of the screw.

2. In a carbon-holding clamp, the combination of a normally-stationary jaw a, a movable j aw h, jointed thereto, provided with two laterally-separated ears b', a double-collared clamping-screw s, tapped into the stationary jaw and passing loosely between said ears and having the faces of the collars adjacent to the vertical edges of the ears beveled or rounded one, substantially as shown and hereinbefore described.

In testimony whereof I have affixed my signature in presence of two witnesses.

VAN A. THOMAS. Vitnesses:

CHARLES IIANNIGAN, GEO. Il. REMINGTON. 

